Radiology - CHAP. 3

Latent period in radiation biology is the time btw?   

Exposure to X-radiation & clinical symptoms

A free radical is …?

an uncharged molecule with an unpaired e- in the outer shell, highly reactive/unstable, & combines = toxins.

Direct radiation injury occurs when?      

Xray photons hit critical targets within a cell.

Indirect radiation injury occurs when?  

Xray photons are absorbed & form toxins.

Which relationship describes the response of tissues to radiation?       

 Linear, threshold

Which factors contribute to radiation injury?        

Total dose, dose rate, age, & cell sensitivity

Radiation injuries that’re not seen in the person irradiated but that occur in future generations are termed? 

Genetics

Which is most susceptible to ionizing radiation?                

Small lymphocyte

The sensitivity of tissues to radiation is determined by?    

Mitotic activity

Which is considered radioresistant?    

 Mature bone cells

An organ that, if damaged, diminishes the quality of an individual’s life is termed?   

Critical

The traditional unit for measuring X-ray exposure in air is termed?   

Roentgen

Which radiation unit is determined by the quality factor?      

   Rem  

The unit for measuring the absorption of xrays is termed?    

  Rad

Which conversion is correct?           

1R=2.58X10^-4C/kg

Which traditional unit does not have an SI equivalent?         

Quality factor

Which measurement is used only for xrays?        

  Roentgen

Which conversion is correct?            

 1 Gy=100rad       1Sv=100 rem         1 rem=radXQF

What‘s approximate average dose of background radiation received by an individual in the US?

300mrem/3.0mSv

What’s the greatest contributor to artificial radiation exposure?        

Medical radiation

The amount of radiation exposure individual receives varies depending on?

Receptor type, collimation, technique

A single intraoral image using a digital sensor results in an effective exposure dose of?    

0.020 mSv

What’s the dose at which leukemia induction is most likely to occur?  

500 mrad (0.005Gy)

Smallest to largest radiation exposure in US→

consumer products, terrestrial, cosmic (space), radon/thoron, & medical procedures.

Smallest to largest effective dose for examination types→

single periapical/rectangular collimation, single bitewing/round collimation, panoramic, complete series/rectangular collimation, & round collimation